1. Field of the Invention
The present invention relates to a disc discrimination device and a disc discrimination method capable of discriminating what type of disc is loaded on a disc apparatus on which a different type of disc such as a CD, DVD and the like can be loaded.
2. Description of the Related Art
Recently, there have been developed disc apparatuses on which a different type of disc can be loaded. In this case, what type of disc is loaded on the disc apparatus must be discriminated.
However, a CD (Compact Disc), DVD (Digital Versatile Disc), CD-ROM, etc. have the same disc diameter of 12 cm and the clamping center hole thereof also has the same diameter. Thus, a type of disc cannot be discriminated from only the shape and size thereof.
To cope with this problem, conventional disc apparatuses employ such a method of discriminating a type of disc loaded thereon that the signal recorded on the disc is read by an optical head by rotating the disc when it is loaded to thereby determine the transfer velocity and arrangement of the thus read signal.
However, the method of discriminating a type of disc loaded on the disc apparatus by rotating the disc and reading its signal by the optical head cannot instantly discriminate the type just after the disc is loaded and a long time is required to the completion of the discrimination.
When, for example, only two types of disc, namely, the CD and DVD are discriminated by the above method, it is sufficient for a control circuit to distinguish only two types of signal. However, in a disc apparatus on which more types of disc are loaded, it is necessary for the control circuit to discriminate a plurality of types of signal and the discrimination method effected by the control circuit is made very complex.
An object of the present invention for solving the above problem of prior art is to provide a disc discrimination device and a disc discrimination method capable of discriminating a disc in a short time without the need of reading the signal recorded on the disc.
Another object of the present invention is to provide a disc discrimination device and a disc discrimination method capable of certainly discriminating respective types of disc even in a disc apparatus on which many types, namely, three types or more of disc are loaded.